We have developed and are continuing to pursue a broad program in molecular approaches to evolutionary problems in plant systems including the use of patterns of flavonoids, terpenes, betalains, alkaloids, nucleic acids, etc., as genetic markers and for studying population structure and the evolutionary history of plant taxa. We now propose to extend our research to include the role that low-molecular weight compounds play in controlling plant-plant, plant-insect, plant-microorganism and animal-animal interactions. The latter project will involve establishing the chemistry and biochemistry of mammalian pheromones. Our analytical capabilities (including computerized GC-MS, C13-NMR, etc.) and library of data on natural products permit the rapid analysis and identification of micro amounts of biological compounds. We are thus able to tackle a wide spectrum of projects involving the roles low-molecular compounds play in biological systems and at the same time develop new aspects of our biochemical systematics program.